Weaning, yearling, and preharvest ultrasound measures of fat and muscle area in steers, bulls, and heifers.

摘要: Longissimus muscle area and fat thickness were measured following weaning, at yearling, prior to harvest using real-time ultrasound, corresponding carcass measurements recorded 3 7 d the preharvest scan in composite steers (n = 116, 447 ± 19 d), bulls 224, 521 11 heifers 257, 532 12 d). Although deposition was limited from weaning coefficients of variation ranged 8.46 13.46% for area, 27.55 38.95% thickness, indicating that significant phenotypic variance exists across genders. Residual correlations, adjusted effects year birth, gender, age measurement, high 0.79 0.87 among ultrasound measures area. correlations also high, ranging 0.64 0.86. Weaning and/or yearling yielded similarly accurate predictions Yearling accounted 13% more observed than measure single-trait prediction models. When both used predict partial R 2 values 0.15 0.61 respectively. The difference between predicted with respect (fat thickness) less 6.45 cm (2.5 mm) 80.2 88.9% (90.3 95%) animals. Preharvest standard errors 4.95 1.51 mm or thickness. These results indicate taken provide predictors traits steers, bulls, heifers.